We propose the continuation of a large-scale derivation strategy to establish a rhesus monkey SPF production program. In 1988, 286 physically, behaviorally, and reproductively healthy conventional rhesus monkeys were dedicated to establishing a rhesus breeding colony free of retroviruses and Herpes B virus (SPF). The initially proposed derivation strategy has exceeded the projected expectations of the first award period by 100%. The intensive viral screening, separation and management of six differently defined animal populations has resulted in 408 animals between one and five years of age that meet the SPF definition. Herpes B virus incidence in this population is zero; there has never been an SRV positive animal in the population and all SRV indeterminates have been removed as have all STLV and SIV positive or indeterminate animals. This population represents the nucleus of our true SPF production colony. Breeding statistics during the past five years have been impressive, considering the disruptive nature of doing intensive viral screening of lab-born infants through sequential single-, pair-, and peer-housing. The success of our large scale derivation strategy has provided vital information for improving the continuation strategy and strengthening assurances that we can establish a well-protected, closed production colony free of the specified pathogens. The professional and technical team that has orchestrated programmatic success to date will continue to implement an even more innovative and improved program. Although establishing the SPF production colony and achieving financial independence will be our primary goal, the grantee institution (University of Texas) is again proposing a programmatic consortium to perform resource relevant investigations and maximize the use of this unique animal population. The consortium goals have direct relevance to enhancing the long-term cost-effectiveness and quality improvement of the SPF production program. The behavioral companion research grant (Bloomsmith) addresses applied behavioral principles to enhance the behavioral competence and well-being of the derived production colony and the future production of behaviorally normal investigative animals and replacement breeders. We are proposing the animal resource support of a subcontract dealing with genetics.